Variable condenser



July 15 1924. I 1,501,543

L. A. HAMMARLUND VARI ABLE CONDENSER Filed Nov. 28, 922 2 Sheets-Sheet 1IN] 'ENTOR %./1JWW A 'I'TOR NE Y5 L. A. HAMMARLUND VARI ABLE CONDENS ERFiled Nov. 28, 1922 2 SheeLsSneet 2 IN VEN TOR shaft 11, which Patentedlluly 15, 1 924.

LLOYD A. HAIKARLUND, OF NEW YORK,

COMPANY, INC-, OF NEW YORK, N.

N. Y., ASSIGNOR TO HAHMABLUND m.

Y., A CORPORATION NEW YORK.

VARIABLE CONDENSER.

Application filed November 28, 1922. Serial No. 008,793.

T 0 all whom it may concern:

Be it known that I, LLOYD A. HAMMAR- LUND, a citizen of the UnitedStates, and a resident of the borough of Manhattan, in the city andState of New York, have invented a new and useful Improvement inVariable Condensers, of which the following is a specification.

In variable condensers for radio use, it has been practically impossiblein many instances to'bring the condenser into nearer than an approximateadjustment for the re sult desired.

The object of my invention is to provide not only the usual primarymeans for bringing the condenser into approximate adjustment, but alsoto provide a secondary means for bringing the condenser into a moreaccurate adjustment to the minutest degree, which is' so especiallydesirable in radio work.

The object of my invention is further to provide a secondary meansworking through the primar means for accomplishing this accurate adustment, sufficient friction being obtained to maintain the condenser inits accurate adjustment under all ordinary conditions. 1 A practicalembodiment of my invention is represented in the accompanying drawin s,in whichig. 1 represents a front view of a variable condenser of wellknown and approved form, with my invention applied thereto.

Fig. 2 represents a side view Fig. 3 represents a top plan. Fig. 4represents a section taken in the plane of the line IVIV of Fig. 1,looking 111 the direction of the arrows.

The outer member 1 of the condenser frame is shown as secured to andspaced from the panel 2 by the screws 3 and spacing blocks 4. The innermember 5 of the condenser frame is shown as secured to and spaced fromthe outer member 1 by the posts 6 and 7, to which posts the stationaryplates 8 of the condenser are permanently secured in their spacedrelationship.

The movable plates 9 of the condenser are secured to the condenseradjusting rock shaft is shown as extending through the anel 2 where itis provided with the usual knob 12 and dial 13. A set screw 14 may beused for fixing the combined knob and dial on the rock shaft with the ofthe same.

dial scale 15 in proper position with respect tothe movable plates 9 ofthe condenser and the fixed pointer 16, which, in the present instanceis shown as secured to the panel 2. by one of the screws 3.

This rock shaft 11, together with the knob, dial scale and pointer serveas the primary means for brin ing the condenser into. its approximate adustment.

Suitable means are provided for limiting the turning movement of therock shaft 11, which carries the movable plates 9 of the condenser, suchmeans bein herein shown as oppositely disposed pins 1%, 18, projectinginwardly from the outer member 1, which pins are positioned to act asstops for a lateral pin 19, projecting from the rock shaft 11.

The secondary means for correcting to the minutest degree theapproximate adjustment, whether above or below the accurate adjustment,is constructed and arranged as follows:

A laterally disposed arm is located adjacent to the outer member 1 ofthe condenser frame, the inner end of which arm is provided with a clamp21, embracing the rock shaft 11, the branches 22, 23 of which clamp areengaged by a screw 24 to draw the clamp into the required frictionalengagement with the rock shaft 11. The outer end of this arm is providedwith a yoke 25, the branches 26, 27 of which engage the opposite sidesof an eccentric cam 28, fixed to a second rock shaft 29, mounted in theouter member 1 of the frame, which rock shaft is provided with a handle30 by means of which the cam 28 may be moved in either direction to rockthe arm 20 and thereby the rock shaft 11 because of the frictionalengagement between the arm clamp 21 and said rock shaft 11. It will beunderstood that this frictional engagement is not sufficient to preventthe turning of the rock shaft 11 by the knob independently of the arm20, but is sufficient to hold the rock shaft in its approximatelyadjusted position; it being understood that the cam 28 holds the arm 20against movement when the rock shaft 11 1s being turned by the primarymeans.

When it is desired to adjust the condenser,

turns in the clamp 21 of the arm 20. After this approximate adjustmenthas been obtained, an extremely accurate adjustment of the condenser maybe obtained by manipulating the cam 0 erating handle 30' to move the camand roc the arm, and thereby the rock shaft 11 either way, to bring theadjustment slightly up or down, as the case may re uire.

It wi 1 be seen that a secondary means'has been provided for bringing acondenser of usual construction, into extremely accurate adjustment,without materially increasing the cost or complication of the same. Itwill also be noticed that this secondary adjustment may be manipulatedfrom a point outside of the immediate sphere of electrical influence.

It is evident that various changes ma be resorted to in theconstruction, form an arrangement of the several parts without departingfrom the spirit and scope of my invention, hence I do not wish to belimited to the particular embodiment herein shown a and described, but

What I claim is 1. In an electric current controlling instrument,primary means including a rock shaft for bringing the instrument into anapproximate adjustment, and secondary means including a swinging armpivoted on and frictionally engaging the rock shaft and a cam operableto swing said arm for turning said rock shaft, to bring the instrumentinto a more accurate adjustment.

2. In an electric current controlling instrument, primary meansincluding a rock shaft for bringing the instrument into an approximateadjustment, and secondary I means including a swinging arm pivoted onand frictionally engaging the rock shaft, a cam engaging said arm and ahandle for moving the cam to swing the arm for turn ing the rock shaft,to bring the instrument into a more accurate adjustment.

3. In an electric current controlling instrument, primary meansincluding a rock shaft for bringing the instrument into an approximateadjustment, and secondary means includingi a swingin arm having itsinner end provi ed with a c amp frictionally embracing said rock shaftand its outer end provided with a yoke, a cam located in said y9ke, anda handle for moving the cam to swing said arm for turning said rockshaft, to bring the instrument into a more accurate adjustment.

4. In a variable condenser, the spaced stationary and movable plates,primary means including the usual knob, dial and movable plate carryingrock shaft for bringing the condenser into an approximate adjustment,and secondary means including a swinging arm pivoted on and frictionallyengaging the rock shaft, and a cam operable to swing said arm forturning said rock shaft, to bring the condenser into a more accurateadjustment.

5. In a variable condenser, the spaced stationary and movable plates,primary means including the usual knob, dial and movable plate carryingrock shaft for bringing the condenser into an approximate adjustment,and secondary means including a swinging arm pivoted on and frictionallyengaging the rock shaft, a cam engaging said arm, and a handle formoving the cam to swing said arm for turning said rock shaft, to bringthe condenser into a more accurate adjustment. 6. In a variablecondenser, the spaced stationary and movable plates, primary meansincluding the usual knob, dial and movable plate carrying rock shaft forbringing the condenser into an approximate adjustment, and secondarymeans including a swinging arm. having its inner end provided with aclamp, frictionally embracing said rock shaft and its outer end providedwith a yoke, a cam located in said yoke, and a handle for moving the camto swing said arm for turning said rock shaft, to bring the condenserinto a more accurate adjustment.

In testimony that I claim the foregoing as my invention, I have signedmy name this 22nd day of May, 1922.

LLOYD A. HAMMARLUND.

